 /*******************************************************************************
  * Copyright (c) 2005 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  ******************************************************************************/

 package org.eclipse.ui.commands;

 import java.util.Collections ;
 import java.util.HashMap ;
 import java.util.Hashtable ;
 import java.util.Map ;
 import java.util.StringTokenizer ;

 import org.eclipse.core.commands.IParameterValues;
 import org.eclipse.core.runtime.IConfigurationElement;
 import org.eclipse.core.runtime.IExecutableExtension;

 /**
  * <p>
  * A generic implementation of <code>IParameterValues</code> that takes advantage
  * of the <code>IExecutableExtension</code> mechanism. The parameter values and names can be
  * specified purely in XML. This can be done as follows:
  * </p>
  * <p><pre><code>
  * &lt;command
  * name="%name"
  * description="%description"
  * categoryId="categoryId"
  * id="commandId"&gt;
  * &lt;parameter
  * id="parameterId"
  * name="%parameterName"&gt;
  * &lt;values class="org.eclipse.ui.commands.ExtensionParameterValues"&gt;
  * &lt;parameter name="%parameterName1" value="parameterValue1" /&gt;
  * &lt;parameter name="%parameterName2" value="parameterValue2" /&gt;
  * &lt;parameter name="%parameterName3" value="parameterValue3" /&gt;
  * &lt;/values&gt;
  * &lt;/parameter&gt;
  * &lt;/command&gt;
  * </code></pre></p>
  *
  * @since 3.1
  */
 public final class ExtensionParameterValues implements IParameterValues,
         IExecutableExtension {

     /**
      * The delimiter between elements if the name-value pairs are specified in a
      * single string.
      */
     public static final String DELIMITER = ","; //$NON-NLS-1$

     /**
      * The parameter values for this instance. This is initialization when the
      * executable extension is created. For example,
      */
     private Map parameterValues = null;

     public Map getParameterValues() {
         return parameterValues;
     }

     public final void setInitializationData(final IConfigurationElement config,
             final String propertyName, final Object data) {
         if (data == null) {
             parameterValues = Collections.EMPTY_MAP;

         } else if (data instanceof String ) {
             parameterValues = new HashMap ();
             final StringTokenizer tokenizer = new StringTokenizer (
                     (String ) data, DELIMITER);
             while (tokenizer.hasMoreTokens()) {
                 final String name = tokenizer.nextToken();
                 if (tokenizer.hasMoreTokens()) {
                     final String value = tokenizer.nextToken();
                     parameterValues.put(name, value);
                 }
             }
             parameterValues = Collections.unmodifiableMap(parameterValues);

         } else if (data instanceof Hashtable ) {
             parameterValues = Collections.unmodifiableMap((Hashtable ) data);

         }

     }
 }

